In a conventional chemical vapor deposition (simply called "CVD" hereinafter) apparatus used for the fabrication of a semiconductor device and the repair of clear mask defects, an object article such as a photomask is held on a fixed holder which is not moved during a process for growing thin films on the object article.
In a repair apparatus for reparing clear photomask defects, a photo-CVD process is utilized to grow a rectangular shaped thin film of a predetermined size on a photomask for reparing a clear defect of a photomask, however, a holder on which the photomask is held is different from the fixed holder of the conventional CVD apparatus. In more detail, an optical focusing or projecting system is utilized to selectively radiate light beam on the clear defect of the photomask, so that the rectangular shaped thin film is grown thereon. When a focusing point is changed from one clear defect of the photomask to another, the photomask is controlled to be moved dependent on the position change of the focusing point because the optical focusing or projecting system is practically impossible to be moved. For this purpose, the holder on which the photomask is held is provided in a chamber of a hermetically sealed structure in which process gas is charged, so that the holder is controlled to be moved, thereby adjusting a thin film growing position of the photomask to the focusing point.
Such a repair apparatus is described on pages 19 and 20 of "Microelectronic Manufacturing and Testing, October 1985", on page 34 of "Laser & Applications, October 1985", and on pages 90 to 100 of "Semiconductor International, January 1986".
In the conventional photo-CVD apparatus, however, there is a disadvantage that the chamber is large in size because it contains a machanism for moving the holder. For this structure, a large amount of process gas mixed of raw material gas and carrier gas must be charged into the large sized chamber in spite of the fact that an amount of the process gas which is necessary to grow a minute thin film selectively on the clear defect of the photomask is small. As a result, much amount of process gas is consumed. Thus, a supply and exhaust system of the process gas is large in size and uneconomical.
There is a further disadvantage that the conventional photo-CVD apparatus is expensive because a structure for safety must be provided to seal the entire gas flow path through which much amount of harmful process gas is circulated. In fact, reacting gas is poisonous because gas which is obtained from the sublimation of carbonyl metal such as carbonyls of Cr., Mo, W etc. is utitized.
There is a still further disadvantage that a thin film of good quality is hard to be grown because a flow control of gas in which process gas is supplied to a thin film growing position and process gas is exhausted therefrom is rather difficult.